Generally, in an electro-photographic image forming apparatus such as a laser printer, an image carrier (photosensitive drum) for carrying a developer image (toner image) and a transfer roller applied with a transfer bias for electrostatically attracting the developer image from the image carrier are provided to contact each other. When a sheet passes between the image carrier and the transfer roller, the transfer roller attracts the developer image, thereby transferring the developer image onto the sheet, such that an image is formed on the sheet.
However, in such image forming apparatus, if the image carrier and the sheet are separated from each other at an upstream of a portion where the image carrier and the transfer roller contact each other in a sheet conveyance direction, electric discharge occurring between the image carrier and the sheet scatters developer to cause the image dirty. In order to cope with this problem, it is proposed to provide a guide plate for bringing the sheet to an image carrier side at the upstream of the above-described portion in the sheet conveyance direction (see JP-A-2003-5535, for example).
In this apparatus provided with the guide plate, immediately after a trailing edge of a sheet passes the guide plate, the sheet is rapidly separated from the image carrier due to the rigidity of the sheet, and thus the image is disturbed in the vicinity of the trailing edge of the sheet.